Hendra virus is one among the two Henipa viruses, the other being Nipah virus. Henipaviruses belong to the paramyxovirus family and are the most virulent among all paramyxoviruses. Fruit bats (flying foxes) of genus Pteropus and Pteropididae family are the natural reservoirs of both Hendra and Nipah viruses.

Today, we will talk about Hendra virus infection as we have covered Nipah virus infection in earlier editions of eMedinewS (see relevant links below) when the outbreak in Kerala first came to light.

1. Hendra virus infection is a rare emerging zoonosis that causes severe and often fatal disease in both infected horses and humans.
2. It was first detected in 1994 following an outbreak of respiratory and neurologic disease in horses and humans in Hendra in Brisbane, Australia.
3. As of July 2016, 53 disease incidents involving over 70 horses have been reported. These were all confined to the north-eastern coast of Australia. A total of seven humans have contracted Hendra virus as ‘spillover’ events from infected horses, particularly through close contact during care or necropsy of ill or dead horses (WHO).
4. Individuals exposed (occupational/ recreational) to horses that have had potential contact with flying foxes in Australia or those living within the distribution of the flying foxes are at risk of acquiring Hendra virus infection.
5. Exposure to body fluids and tissues or excretions of infected horses may result in humans acquiring the infection. Exposure to virus in the urine of infected flying foxes transmits the infection to horses. No case of human-to-human transmission has been documented so far.
6. Diagnostic tests include ELISA (IgG and IgM; serum or cerebrospinal fluid [CSF]), real time polymerase chain reaction (RT-PCR; serum, CSF, or throat swabs) and virus isolation (CSF or throat swabs). All specimens of suspected cases must be handled in high containment laboratories.
7. The incubation period is 9-16 days.
8. Clinically, Hendra virus infection presents with severe flu-like illness. Encephalitis may occur in some cases. These signs and symptoms may progress to fatal respiratory or neurological disease.
9. Case fatality rate is high (57%).
10. There is no specific treatment for human cases of Hendra virus. Supportive care is the mainstay of management. The antiviral drug, ribavirin has been shown to be effective against the viruses in vitro; its effectiveness or beneficial effects in clinical cases is still unclear.
11. Prevention: Early diagnosis of the disease in the intermediate animal host is probably the most important way by which transmission of infection to humans can be prevented. Avoiding contact with the infected horses and use of personal protective equipment are some preventive measures. A commercial vaccine has been recently licensed in Australia for horses and could be beneficial for other animal species and eventually humans.

(Source: CDC)

Links on Nipah virus infection

1. http://blogs.kkaggarwal.com/2018/05/nipah-virus-encephalitis-a-newly-emerging-disease/
2. http://blogs.kkaggarwal.com/2018/05/health-ministry-advisory-on-nipah-virus/
3. http://blogs.kkaggarwal.com/2018/05/simple-measures/
4. http://blogs.kkaggarwal.com/2018/05/awareness-needs-to-be-created-to-dispel-fears-about-nipah-virus/
5. http://blogs.kkaggarwal.com/2018/05/number-of-3/

Dr KK Aggarwal

Padma Shri Awardee

Vice President CMAAO

Group Editor-in-Chief IJCP Publications

President Heart Care Foundation of India

Immediate Past National President IMA